MontecarloDrag

iTrader: (3)

Hello.

I have a problem I have never seen. Hope I get more answers here.

I swapped a 2003 5.3L into a 88 C10 pickup. All wiring and mechanical work is done, but I'm having an issue.
If I disable any DTC (with HPtuners) the engine runs poorly and dies, no throttle response. I tried write cal only and write entire, no difference.
If I change anything else to the tune, it runs fine. It runs pretty good with the stock tune, however I want to install a MIL light so I need to disable all codes for deleted stuff (rear O2, fuel tank, evap, cats, etc).
Any DTC I change it makes the engine die.

I hope somebody have an insight of whats happening, I can't find the reason for this problem, I have 3 days trying.

Here is the tune, first file it's stock only VATS disabled. Works good.
Second is the same with a few codes disables. Works like ****

Thanks

mannyman84

iTrader: (2)

Do you delete the codes with engine on or off? Delete with engine off.

MontecarloDrag

iTrader: (3)

yes i disabled them in the tune (not with scanner)
then i flash the tune to pcm and engine runs poorly and dies.
if i flash stock tune back it works good again.
i can change everything else to tune with no problems, only disabling dtc's cause the issue

thanks

ZL1Killa

iTrader: (17)

don't some DTCs have to be on or set to not reported / no mil in order for the engine to operate?
I know if you turn the MAF completely off (completely) engine won't run at all

MontecarloDrag

iTrader: (3)

Yes I thought of that, but it does it with any DTC I disable, even rear O2's.
It doesn't matter if it's set to no mil light, or no problem reported, as long as it's changed from stock it causes failure.

I even flashed a newer OS and made the same thing.

jimmyblue

iTrader: (11)

This is all pretty strange, but my gut suspicion is that
one of the codes is putting you into a fault mode where
you run right, and the straight tune, you've got some
issue. Like having a busted MAF and you run crappy
until it faults back to SD - or whacked O2 sensors, in
closed loop you'd trim off into the weeds but faulted
to open loop, you're on the base / nominal fueling.

Not saying this is it, just a couple of examples.

foff667

iTrader: (2)

I would lean towards a pcm issue in this case. My reason being is the VCM id number in the file you posted 010002774274

I have NEVER seen a vcm id number like this from the factory which leads me to believe this pcm was likely previously tuned possibly at the binary level and someone could've easily screwed up the code.

I've seen guys fry their pcm's by entering the wrong data in hex so this isn't far fetched and makes alot of sense after seeing the vcm id number like that.

MontecarloDrag

iTrader: (3)

I'm also thinking a PCM issue.
However this PCM was never messed with, I compared the tune I read from it with a know stock and found no differences.

Even if that was the case, flashing a newer stock tune using write entire should fix it shouldn't it? and it didn't, the behavior was exactly the same.

I'm going to buy a new PCM.
Good point, it doesn't have a MAF. I'm gonna try a new MAF before i buy another PCM

Thanks for your answers